This invention relates to detergent cleaning compositions which are particularly suitable for use in automatic dishwashers. In particular, the compositions herein comprise a nonionic surface-active agent, and an effective amount of an enzyme mixture which comprises a proteolytic enzyme having a proteolytic activity of 80 to 100% of maximum activity when measured at pH 12 using the Anson hemoglobin method carried out in the presence of urea, and an amylolytic enzyme, wherein the ratio of said proteolytic enzyme to said amylolytic enzyme is from about 4:1 to about 1:4 by weight. The compositions of this invention are capable of providing, during conventional use, markedly enhanced cleaning performance for a range of soils, in comparison with compositions containing the more conventionally used enzymes. The instant compositions, in addition to the essential components, preferably comprise conventional dishwashing composition additives, in the art-established levels to achieve their known function. Examples of such additives include sodium silicate solids, sodium carbonate, sodium bicarbonate, sodium sulfate, and sodium phosphate. It is noteworthy that the compositions herein are capable of providing excellent dishwashing performance in the presence of a reduced level of phosphorus-containing detergent builders, or in essentially phosphate-free compositions as well as in fully built phosphate compositions.
Conventional automatic dishwashing compositions usually contain a low foaming surface-active agent, a chlorine bleach, alkaline builder materials, and usually minor ingredients and additives. The incorporation of chlorine bleaches requires special processing and storage precautions to protect composition components which are subject to deterioration upon direct contact with the active chlorine. The stability of the chlorine bleach is also critical and raises additional processing and storage difficulties. In addition, it is known that automatic dishwasher detergent compositions may tarnish silverware and damage metal trim on china as a result of the presence of a chlorine-containing bleach therein. Accordingly, there is a standing desire to formulate detergent compositions for use in automatic dishwashing operations which are free of active chlorine and which are capable of providing overall hard surface cleaning and appearance benefits comparable to or better than active chlorine-containing detergent compositions. This reformulation is particularly delicate in the context of automatic dishwashing operations, since during those operations, the active chlorine prevents the formation and/or deposition of troublesome protein and protein-grease complexes on the hard dish surfaces and no surfactant system currently known is capable of adequately performing that function.
The disclosures of U.S. Pat. No. 3,549,539 to Mallows, incorporated herein by reference, relates to machine dishwashing powders containing a nonyl phenol-5-EO or a condensation product of a random C.sub.11 to C.sub.15 secondary alcohol and ethylene oxide with an HLB (hydrophilic-lipophilic balance) value between 11.5 and 13.5 and a polyethylene oxide-polypropylene oxide condensate that consists of between 5 and 25% polyethylene oxide and 95 to 75% polypropylene oxide and has a molecular weight between 1500 and 2700. It is disclosed that in addition to the above surfactant combination the machine dishwashing powder will normally contain from 5 to 30% of a silicate, such as sodium metasilicate, from 5 to 30% of an oxidizing agent, from 25 to 70% of a calcium ion sequestrant and from 1 to 20% of an inorganic filler salt, such as sodium carbonate or sodium sulfate. The oxidizing agent included may be chlorinated sodium orthophosphate, chlorinated isocyanurate and perborate possibly with a copper catalyst or an organic activator. Additional disclosures relative to bleach-containing detergent compositions for use in automatic dishwashers can be found in, for example, U.S. Pat. Nos. 3,410,804; 3,390,092; 3,248,330; and 3,595,968, incorporated herein by reference.
Various attempts have been made to formulate bleach-free low foaming detergent compositions for automatic dishwashing machines, containing particular low foaming nonionics, builders, and filler materials. As an example, U.S. Pat. No. 3,022,250 to Grifo, incorporated herein by reference, relates to low-sudsing detergent compositions especially adapted for automatic dishwashing machines, containing a phenol having therein an aliphatic substituent with an average of 9 carbon atoms per chain and a second substituent comprising condensed ethylene oxide in an average number of four molecules per molecule of phenol, together with builder consisting essentially of a mixture of sodium metasilicate and sodium tripolyphosphate in the proportion of one part of metasilicate to three parts of tripolyphosphate, the builders being present in the proportion of 95 parts of builder mixture to 5 parts of alkyl phenyl ethylene oxide. Thus, the art has recognized the desirability of formulating an effective detergent composition for use in automatic dishwashers, which does not require the inclusion therein of a chlorine-containing bleach.
Another problem recognized in the art is that of effectively incorporating enzymes in a highly alkaline detergent composition for use in an automatic dishwasher, while preventing the degradation of the enzymes, during use, and thereby their loss of cleaning effectiveness. U.S. Pat. No. 3,472,783; to Smillie, recognizes that the addition of an enzyme to an aqueous, alkaline detergent composition will result in the degradation, and thereby the loss of effectiveness, of the enzyme. The compositions of that patent do not contain alkaline builder salts in order to alleviate the enzyme degradation problem.
French Pat. No. 2,102,851 to Colgate-Palmolive, pertains to rinsing and washing compositions for use in automatic dishwashers. The compositions disclosed have a pH of about 6 to 7 and contain an amylolytic and, if desired, a proteolytic enzyme, which have been prepared in a special manner from animal pancreas and which exhibit a desirable activity at a pH in the range of about 6 to 7. German Pat. No. 2,038,103 to Henkel & Cie. relates to aqueous liquid or pasty cleaning compositions containing phosphate salts, enzymes and an enzyme stabilizing compound. U.S. Pat. No. 3,799,879 to Francke et al, teaches a detergent composition for cleaning dishes, with a pH of from 7 to 9 containing an amylolytic enzyme, and in addition, optionally a proteolytic enzyme.
Concurrently filed U.S. Patent application Ser. No. 669,415, entitled "Enzyme-Containing Automatic Dishwashing Detergent Composition", inventors Geoffrey Place and Edward J. Maguire, Jr., relates to bleach-free automatic dishwashing compositions comprising an alkoxylated nonionic surface-active agent, and particular enzymes, preferred ones of which exhibit a proteolytic activity of at least 80% of maximum activity when measured at pH 12 using the Anson hemoglobin method carried out in the presence of urea.
U.S. Pat. No. 3,827,938 to Aunstrup et al, discloses specific proteolytic enzymes which exhibit high enzymatic activities in highly alkaline systems. Similar disclosures are found in British Patent Specification No. 1,361,386, to Novo Terapeutisk Laboratorium A/S. British Patent Specification No. 1,296,839, to Novo Terapeutisk Laboratorium A/S, discloses specific amylolytic enzymes which exhibit a high degree of enzymatic activity in alkaline systems.
Thus, while the prior art clearly recognizes the disadvantages of using aggressive chlorine bleaches in automatic dishwashing operations and also suggests bleach-free compositions made by leaving out the bleach component, said art disclosures are silent about how to formulate bleach-free automatic dishwashing compositions capable of providing superior performance during conventional use.
Accordingly, it is an object of this invention to formulate detergent compositions, which may be formulated without bleach, capable of providing superior cleaning and antiredeposition characteristics in automatic dishwashing operations.
It is an additional object of this invention to effectively and stably incorporate enzymes in detergent compositions for use in automatic dishwashing operations with a view toward optimizing cleaning performance of the compositions.
It is a further object of this invention to incorporate a unique enzyme mixture in detergent compositions for use in automatic dishwashing operations capable of providing at least equal or better performance than automatic dishwashing compositions commercially available now.
It is still a further object of the invention to provide enzyme containing compositions in a product form which reduces the tendency of the enzymes to become deactivated during the use of the product.
The above and other objects are now achieved by formulating a detergent composition for use in automatic dishwashing operations, comprising a nonionic surface-active agent and a select binary enzyme system.